Ischemic Heart Disease 2

Question 1

When diagnosing the stable phase of CAD, what kind of past medical history do we look for?

Answer 1

Chest pain, dyspnea, risk factors. (Risk factors increase the likelihood that the symptoms are an indication of CAD and not something else)

Question 2

When diagnosing the stable phase of CAD, what kind of physical examination findings can we expect?

Answer 2

Physical examination for stable phase of CAD can present as quite normal. Sometimes, you may be able to find evidence of cardiac dysfunction from prior myocardial damage (congestive heart failure), or evidence of atherosclerosis in other vascular beds

Question 3

What are some clinical tools that you can use to help diagnose the stable phase of CAD?

Answer 3

ECG (both at rest and with exercise stress test), non-invasive imaging such as echocardiography, nuclear medicine (perfusion imaging), ultrafast CT, or coronary angiography.

Question 4

What do you look for on the ECG for diagnosing stable phase of CAD?

Answer 4

In resting ECG: - ST segment changes (usually depression) - T wave inversion - Q-waves (indicate prior infarction) In exercise ECG: - dynamic ST segment changes

Question 5

Is resting ECG or stress test ECG more sensitive and specific for diagnosis of CAD?

Answer 5

Exercise ECG is more sensitive and specific, but still suboptimal (~70% and 75% respectively)

Question 6

Is resting ECG a sensitive test for diagnosing coronary obstruction?

Answer 6

No

Question 7

What does an ischemic response look like on the stress test ECG?

Answer 7

An ischemic response will present as horizontal or downsloping ST depressing with exercise, reflecting subendocardial ischemia.

Question 8

Which part of the LV is most prone to ischemia/hypoperfusion?

Answer 8

Subendocardial

Question 9

What is functional information and how does it add to interpretation of testing for CAD?

Answer 9

Functional information (e.g. exercise time, maximum workload, and exercise-induced symptoms) bears a relationship with the severity of the underlying disease

Question 10

What kind of imaging helps improve sensitivity and specificity of stress testing?

Answer 10

Radiopharmaceuticals (for perfusion imaging) and echocardiography (for wall motion)

Question 11

What is the S4 heart sound indicative of?

Answer 11

Hypertension or hypertrophy of the LV

Question 12

How are carotid artery bruits used for diagnosis?

Answer 12

Carotid artery bruits are turbulent flow sounds that can give you a clue as to the presence of atherosclerosis in the coronary vessels. Although this is a different site, carotid artery is easily accessible and if atherosclerosis is present in the carotid artery, it is likely that it may be present in coronary arteries as well.

Question 13

If ECG at rest is normal but ST elevation is found in peak exercise ECG, what is this diagnostic of?

Answer 13

This is diagnostic of Stable Angina. Stable phase of CAD

Question 14

How can perfusion imaging be used to localize areas of possible coronary artery occlusion?

Answer 14

If you use perfusion imaging to compare perfusion during stress against perfusion during rest, you can identify which areas of the heart have less perfusion during stress and those are the areas that have possible occlusions.

Question 15

How do you treat a stable angina patient? What 4 kinds of medications would you give?

Answer 15

1. Anti-anginal agents (nitrates, beta blockers) 2. Anti-hypertensives (to control BP) 3. Statins (lipid-lowering medication) 4. Aspirin (anti-platelet therapy)

Question 16

What is coronary angiography and how is it used to help treat patients?

Answer 16

Coronary angiography gives a picture of the vessel lumen, but does not tell us about vessel wall. This makes it a great tool for detecting coronary obstruction causing anginal symptoms but it’s not as good for predicting future events. It serves as a guide for therapeutic interventions like angioplasties and bypass surgeries.

Question 17

Why is it easy for angiography to underestimate pathologic extent of CAD?

Answer 17

Because, it only images the lumen. There can be significant stenosis in the vessels but it may not look like it in the angiography because, many times, the vessels grow in circumference when the plaques build within them.

Question 18

Why can asymptomatic CAD patients just drop dead?

Answer 18

Because, if they have significant plaques but are still in the stable phase of CAD, it is still possible for a plaque to rupture and for a thrombotic event to occur killing the patient. This is why risk factor mitigation is important, not just treating symptoms.

Question 19

How can you use fractional flow reserve to estimate severity of a coronary lesion?

Answer 19

If the ratio of distal coronary/aortic pressure

Question 20

How are CT scans used to help diagnose coronary atherosclerosis?

Answer 20

CT scan can image coronary calcium. When atherosclerosis develops, there is recurrent injury to tissue in the vessel wall which is followed by calcium deposition. The amount of calcium doesn’t tell you how much plaque there is but it indicates that there is atherosclerosis. The more coronary calcium seen, the greater the risk of a future coronary event.

Question 21

What 3 therapeutic lifestyle modifications should be used to treat stable coronary artery disease?

Answer 21

Diet, exercise, smoking cessation

Question 22

What 4 drug classes are proven to improve prevention of coronary events?

Answer 22

Anti-hypertensives, statins, aspirin, B blockers and ACE inhibitors (if prior MI with reduced LV function)

Question 23

What are the 2 operations that can help with revascularization?

Answer 23

Coronary angioplasty, coronary artery bypass surgery

Question 24

For smoking cessation, how many years after quitting smoking is your risk of coronary events returned to the level of “never-smoked”?

Answer 24

10 years

Question 25

Treatment of _____ can be effective in reducing significant risk in which stroke, coronary heart disease, congestive heart failure, cerebrovascular disease, and overall death from cardiovascular risk.

Answer 25

hypertension

Question 26

Secondary prevention of cardiovascular events can be significantly achieved by giving _____, _____, ______, and _____.

Answer 26

Statins, aspirin, B blockers, and ACE inhibitors significantly improve mortality rate of patients who have already had an MI.

Question 27

What are the 6 things done for acute treatment of unstable angina?

Answer 27

1. Hospitalization 2. Nitroglycerin (vaso dilator) 3. Beta blockers 4. Aspirin and other anti-platelet agents (e.g. clopidogrel) 5. Anticoagulation (heparin) 6. Usually catheterization and coronary intervention (within hours of diagnosis)

Question 28

_____ reduces the risk of further ischemic events in unstable angina.

Answer 28

Early coronary angioplasty! Studies have shown that when invasive strategy is applied earlier, the probability of death or MI is significantly decreased compared to watching and waiting. So, we are quick to bring patients to the cath lab if they present with unstable symptoms.

Question 29

What was the initial problem/challenge with balloon angioplasties? and what was the solution?

Answer 29

Originally, the problem with balloon angioplasties was acute re-occlusion. The vessel would just re-occlude where the plaque was disrupted. The solution to this was the use of stents and anti platelet drugs.

Question 30

What was the problem with stents?

Answer 30

Restenosis. While stents did prevent acute re-occlusion at the site of plaque disruption, there is gradual fibrotic tissue formation to the foreign body (stent) which causes narrowing of vessel at the location of the stent. You can think of it as a keloid at the site of the vessel wall.

Question 31

In about how many stent cases does restenosis occur?

Answer 31

10-15%

Question 32

What is diaphoresis?

Answer 32

Sweating

Question 33

How do you treat acute myocardial infarction with ST elevation?

Answer 33

Treatment may be initiated in the field. Immediate aspirin, nitroglycerin, and B blocker Repercussion therapy ASAP (usually coronary angioplasty. If unavailable, then use thrombolytic therapy)

Question 34

If coronary angioplasty isn’t available for reperfusion therapy, what should be done instead?

Answer 34

Thrombolytic therapy

Question 35

When is CABG indicated instead of angioplasty?

Answer 35

When certain coronary obstructions cannot be treated easily with angioplasty (e.g. multiple obstructions)

Question 36

In randomized clinical trials, are CABGs shown to reduce mortality more compared to angioplasty?

Answer 36

YES. CABG reduces mortality more than angioplasty. However, in emergent situations, angioplasty is still faster.

Question 37

What are the 2 principal grafts for CABG?

Answer 37

Internal mammary artery and saphenous vein

Question 38

Are prosthetic grafts effective for CABG?

Answer 38

NO. Prosthetic grafts have not proven to be as successful as autografts.

Question 39

Why are internal mammary arteries great for CABG?

Answer 39

Because, for unknown reasons, internal mammary arteries are shown to be patent long after surgery and are for some reason not as often sites of atherosclerosis.

Question 40

Are one or both internal mammary arteries typically used for CABG?

Answer 40

It depends… but typically only one. The other one is left alone so there is enough blood for healing etc.

Question 41

Is internal mammary artery better or saphenous vein better for CABG?

Answer 41

Internal mammary. Because, internal mammary is an artery. The saphenous vein has a much larger diameter than the arteries being bypassed–it can develop hyperplasia over time and become “arterialized” but the patency of internal mammary artery grafts over time is greater than that of saphenous veins.

Question 42

What are the rough percentages of amount of myocardium perfused by the 3 main coronary arteries?

Answer 42

50% done by Left Anterior Descending, 25% done by Right Coronary Artery, 25% done by Circumflex Coronary Artery

Question 43

What are the 3 main coronary arteries?

Answer 43

Right Coronary Artery, Left Anterior Descending (branch of Left Coronary Artery), Circumflex Coronary (branch of Left Coronary Artery)

Question 44

In CABG, where is the internal mammary artery bypass usually attached? (which coronary artery?)

Answer 44

Usually, internal mammary artery bypass will be used to graft at the site of Left Anterior Descending coronary artery (placed beyond the site of stenosis being bypassed).

Question 45

What is the natural origin of the left internal mammary artery?

Answer 45

Left subclavian artery

Question 46

For CABG using saphenous vein, there needs to be a surgical creation of anastomosis. Where are the sites?

Answer 46

The proximal site is done at the root of the aorta, and the distal anastomosis would go at the coronary artery beyond the site of stenosis being bypassed.